Method and apparatus to recover from an erroneous logic state in an electronic system

ABSTRACT

An electronic system includes circuitry to detect errors in logic state in the system and to initiate corrective action when one or more errors are detected. In some embodiments, redundant information is stored within a system that is associated with an operational state of the system. If the operational state of the system is subsequently corrupted as a result of an electrical or mechanical overstress condition, resulting errors may be detected by comparing or otherwise processing the stored operational state information and the redundant information.

FIELD

Subject matter disclosed herein relates generally to electronic systemsand devices and, more particularly, to techniques and circuits forrecovering from errors in electronic systems and devices caused byinterference and/or electrical or mechanical overstress conditions.

BACKGROUND

Electronic systems and devices may be subject to interference andelectrical or mechanical overstress conditions that undesirably altertheir operational states. One area of electronics that is particularlyprone to such stresses is automotive sensors. In automobiles, acombination of multiple mechanical and electrical systems are installedin close proximity and operated in varied environments. This creates anincreased likelihood of electrical interference and sudden motion thatcan result in errors within a sensor. In many cases, a sensor willreturn to normal operation after a stress is applied. However, in somecircumstances, the stress may cause a change to an electronic componentor device that does not allow the sensor to return to correct operationwithout additional intervention. As can be appreciated, errors inducedin this manner are undesirable in all electronics applications, but theyare of particular concern in applications where human safety isinvolved, such as automobiles and other vehicles.

While many techniques exist for storing electronic data, contemporarycircuit design overwhelmingly favors the use of digital circuitry toperform this function. In a sensor based application, the informationbeing stored within digital storage circuitry may include theoperational state of the sensor circuitry (e.g., state informationwithin the state register of a state machine) and/or information aboutsensor inputs (e.g., sensor information stored since power on).Alteration of any of this date can lead to a malfunction of the sensoror other system. There is a need for techniques and circuits foridentifying the occurrence of errors in electronic systems caused byoverstress conditions. There is also a need for techniques and circuitsfor recovering from such errors.

SUMMARY

In accordance with one aspect of the concepts, systems, circuits, andtechniques described herein, an electronic system comprises: firstdigital storage circuitry to store a current operational state of theelectronic system; operational logic to determine a next operationalstate of the electronic system based, at least in part, on an inputsignal; redundancy logic to generate redundant information associatedwith the next operational state determined by the operational logic;second digital storage circuitry to store the redundant information; anderror checking logic to process the current operational state stored inthe first digital storage circuitry and the redundant information storedin the second digital storage circuitry to determine whether a errorexists in the electronic system, the error checking logic includingcorrection logic to initiate corrective action for the electronic systemif an error is detected by the error checking logic.

In accordance with another aspect of the concepts, systems, circuits,and techniques described herein, a method for use in detecting andrecovering from errors in an electronic system comprises: receiving oneor more inputs signals; processing the one or more input signals todetermine a next operational state associated with the electronicsystem; storing the next operational state information; processing thenext operational state information to generate redundant information;storing the redundant information; processing the stored operationalstate information with the stored redundant information to determinewhether one or more errors exist in the operational state information;and initiating corrective action if one or more errors are detected inthe stored operational state information.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing features may be more fully understood from the followingdescription of the drawings in which:

FIG. 1 is a block diagram illustrating an exemplary system for detectingand recovering from errors caused by electrical and/or mechanicalstresses in accordance with an embodiment; and

FIG. 2 is a flow diagram illustrating a process for detecting andrecovering from errors in an electrical system in accordance with anembodiment.

DETAILED DESCRIPTION

Techniques, devices, and circuits described herein relate to thedetection of and recovery from errors in electronic systems caused byelectrical, mechanical, and/or thermal stresses applied to the systemsduring operation. In some embodiments, the techniques, devices, andcircuits may be implemented within systems that use sensor elements todetect and measure one or more operational parameters of a largersystem, (e.g., a magnetic position sensor system for use in automobileapplications, etc.). In the discussion that follows, various principles,techniques, features, and circuits will be described in the context ofsensor based systems. It should be appreciated, however, that many otherapplications also exist.

In an electronic system, operational data is often stored in one or moredigital memory locations or registers during system operation. Theoperational data that is stored within an electronic system at aparticular point in time may be referred to as the current “state,” or“logic state,” or “operational state” of the system. If one or morestresses occur during system operation, such as external noise,interference, or physical impact on the system, errors may occur in thestored values that can negatively affect system operation. In somecases, the negative effect may be short-lived, lasting only as long asthe external stimulus itself. In other cases, the error may affectoperation over an extended time period, causing major operational errorsor complete breakdown of the system.

In some electronic systems, the system may only be capable of operatingin a finite number of operational states (e.g., a finite state machine).In such a system, a next state may depend, for example, on a currentstate of the system and current inputs to the system. The inputs to thesystem may be related to, for example, measurements of one or moreoperational parameters of the system made by sensor elements in thesystem, or some other data. After a next operational state has beendetermined for the system, state information may be stored within one ormore state registers (or other digital storage locations) of the system.As will be appreciated, any errors that occur in the state informationstored in a system may impact future operation of the system. That is,incorrect state information may cause a system to think that it is in adifferent state than it actually is, thus causing all future states, anddecisions made based on those states, to be in error. Therefore, it isdesirable that such errors be detected and appropriate corrective actionbe taken as early as possible.

FIG. 1 is a block diagram illustrating an exemplary electronic system 10that is capable of detecting and recovering from errors in logic statecaused by electrical and/or mechanical stresses in accordance with anembodiment. Electronic system 10 of FIG. 1 may be, for example, a sensorsystem for use within an automobile or other vehicle, although othertypes of systems may alternatively be used. An exemplary sensor systemthat could benefit from the principles and techniques described hereinis described in U.S. Pat. No. 5,650,719, which is co-owned with thepresent application and is hereby incorporated by reference in itsentirety. As shown in FIG. 1, system 10 may include: operational logic12, an operational register 14, redundancy logic 16, a redundancyregister 18, and error checking logic 20. System 10 is capable of beingin any of a number of different operational states at a particular pointin time. Operational register 14 is operative for storing a currentoperational state of system 10. Operational logic 12 is operative fordetermining a next operational state of system 10 based on, for example,a current operational state of the system and current system inputs.Operational logic 12 may include, for example, combinational logiccircuitry in some implementations. As will be described in greaterdetail, redundancy logic 16, redundancy register 18, and error checkinglogic 20 may be used to identify errors in logic state informationstored in operational register 14 before the errors have a chance tocompromise system operation. Error checking logic 20 may also includecircuitry for initiating corrective action when errors are detected inthe system state information.

In sensor-based applications, the information stored within operationalregister 14 may include, or be derived from, information collected byone or more sensor elements 26 in system 10. Some or all of theinformation stored within operational register 14 may also include stateinformation associated with one or more state machines of system 10. Asdescribed above, operational logic 12 is operative for determining anext operational state of system 10. Operational logic 12 may also beoperative for generating the output of system 10 (e.g., a sensed signal,etc.). As shown, operational logic 12 may receive input information atan input port 22 for use in determining the next operational state.Operational logic 12 may also receive information identifying thecurrent operational state of system 10 at a second input 24. Operationallogic 12 may use the input information and/or the current stateinformation to determine the next operational state.

After operational logic 12 has determined the next operational state,the state information may be stored within operational register 14. Oncestored, in operational register 14, the next operational state becomesthe current operational state of system 10. As shown, the currentoperational state stored in operational register 14 may be coupled backto input 24 of operational logic 12 for use in determining a nextoperational state. In some embodiments, system 10 of FIG. 1 may be asynchronous circuit operating in conjunction with a clock signal. Inthese implementations, a new operational state may be stored inoperational register 14 for each new clock cycle. Non-synchronousimplementations also exist.

In some embodiments, the operational state information stored withinoperational register 14 may include state information for the fullelectronic system that includes the register 14 (e.g., a magnetic fieldsensor within an automobile, etc.). In other embodiments, operationalregister 14 may include only a portion of the state information, of thefull system (e.g., the operational state of a single state machine inthe system, information associated with a particular measured parameterin the system, etc.). In some implementations, multiple differentversions of system 10 of FIG. 1 may be present within a larger system todetect errors in different portions of the state information of thelarger system.

As described above, in some embodiments, some or all of the informationstored within operational register 14 may be state informationassociated with a state machine of the underlying system. In suchembodiments, operational logic 12 may determine the next operationalstate based on the current operational state of system 10 and inputinformation received at input 22. That is, given the current state ofthe state machine, the input information may dictate which next statethe state machine is to enter.

In other embodiments, some or all of the operational state informationstored in operational register 14 may be related to measurements ofoperational parameters made by sensor elements 26 associated with system10. For example, in a proximity detector that is designed to detect theapproach and retreat of individual teeth of a rotating gear based onmagnetic fields, the detector may keep track of the maximum and minimummagnetic field intensities measured during the detection process toestablish, for example, detection thresholds. This maximum and minimummagnetic field intensity information may make up part of the currentoperational state of system 10 stored in operational register 14. Insome sensors, instead of detecting gear teeth, the sensor may detect thedifferent magnetic domains of a rotating ring magnet. In these sensors,maximum and minimum magnetic field intensities may also be tracked, andthese values may also make up part of the current operational state ofthe sensor system. Other or alternative types of measured parameter datamay also be part of the state information stored in operational register14 in other embodiments.

In some operational scenarios, external stresses may be placed uponsystem 10 that cause the state information stored, within operationalregister 14 to have one or more errors. For example, large interferencesignals that occur during a write operation may cause data to beincorrectly recorded within a register or memory location. In somecases, interference may also cause information already stored within aregister or memory to change state. Once an incorrect value is storedwithin operational register 14, subsequent operation of system 10 may becorrupted. That is, all future state determinations of operational logic12 may be based upon an incorrect current state. In this manner, thecurrent error can carry through to all future system operation unlesscorrective action is taken. For example, if the system 10 includes astate machine, external stresses may cause an incorrect state to bestored in operational register 14 for the state machine. Because thecurrent state is incorrect all future state determinations made byoperational logic 12 may also be incorrect. Similarly, if maximummagnetic field intensity information is stored in operational register14 for use in detection, threshold determination, external stresses maycause the maximum intensity value to be increased by a large amount.This error may then cause incorrect threshold values to be calculated inall subsequent operation.

To prevent problems related to errors in state information, redundancylogic 16, redundancy register 18, and error checking logic 20 may beused to identify errors in the stored state information before they havea chance to compromise subsequent system operation. In someimplementations, redundancy logic 16, redundancy register 18, and errorchecking logic 20 may be made a part of an initial system design, inother implementations, redundancy logic 16, redundancy register 18, anderror checking logic 20 may be added to an already existing system as aretrofit, without impacting the existing system design.

As shown in FIG. 1, redundancy logic 16 may be coupled to receive stateinformation associated with a next operational state from operationallogic 12. Redundancy logic 16 may use this state information to generateredundant information. The redundant information may take many forms andis selected to be useable by error checking logic 20 to identify errorsin the stored state information. The redundant information may then bestored within redundancy register 18 at about the same time that thestate information for the next operational state is stored inoperational register 14. Error checking logic 20 may continually processthe redundant information stored in redundancy register 18 and the stateinformation stored in operational register 14 to determine whether anerror has occurred in system 10. If the two pieces of information arenot compatible, then it may be assumed that an error has occurred andcorrection logic 28 within error checking logic 20 may initiatecorrective action. If the two pieces of information are compatible, thencorrection logic 28 may allow system 10 to continue operating in itsnormal manner. In at least one implementation, error checking logic 20may process the redundant information and the state information to checkfor an error condition for each cycle of a clock signal, although othertiming schemes may alternatively be used.

The redundant information generated by redundancy logic 16 may includeany type of information that may subsequently be used to “check” theaccuracy of the state information stored within operational register 14.In a relatively simple implementation, the redundant information mayinclude a single parity hit. The parity bit may be generated, forexample, so that the bits of the next operational state determined byoperational logic 12, plus the parity bit, will result in an even (orodd) number of ones. The parity bit may be stored within redundancyregister 18. When a parity bit is used, error checking logic 20 mayperform an error check by, for example, retrieving state informationfrom operational register 14 and the parity bit from redundancy register18 and determining whether the total number of ones for both pieces ofinformation is even (or odd). If not, it may be assumed that at leastone error exists in the state information and corrective action may beinitiated. As will be appreciated, the parity bit approach will not workif there are two bit errors (or an even number of bit errors) within thestate information.

In some embodiments, one or more error detection or error correctioncodes may be used to generate the redundant information. As is known,various error detection codes exist that allow a user to detect multipleerrors within corresponding information (e.g., checksum codes, cyclicredundancy checks, hash functions, etc.), typically up to a maximumnumber of errors. In some implementations, redundancy logic 16 maygenerate the redundant portion of an error detection codeword for thenext operational state and store the redundant portion in redundancyregister 18. Error checking unit 20 may then execute a correspondingerror detection process using the information from operational register14 and redundancy register 18 to determine whether any errors exist inthe state information.

Error correction codes that are capable of detecting and also correctingerrors in the state information may be used in some implementations.When an error correction code is used to generate the redundantinformation, error checking logic 20 may, in some embodiments, only usethe error detection capability of the code to detect errors in the stateinformation. In other implementations, however, the error correctingcapabilities of the code may be used to correct the state informationstored within operational register 14 as part of the corrective actionof error checking logic 20.

In some embodiments, the redundant information stored in redundancyregister is may include a full copy of the next operational stateinformation generated by operational logic 12. In these embodiments, theerror check performed by error checking logic 20 may comprise a simplebit by bit comparison. As will be appreciated, the method selected toprovide the redundant information in a particular implementation willtypically depend on factors such as the frequency of undetected errorsthat is deemed tolerable in the system, the computational resources thatare available for forming and processing the redundant information, theelectrical power available to power the computational resources, thespeed with which the redundancy/detection calculations can be performed,and/or other factors.

As described above, errors within the state information stored withinoperational register 14 are undesirable because they can compromise bothpresent and future operation of fee system. Therefore, the correctiveaction that is initiated by error checking unit 20 when one or moreerrors are detected may be directed toward placing the system 10 backinto a safe state that will not compromise future operation. In at leastone implementation, error checking unit 20 may initiate a full systemreset when one or more errors are detected within the state information.When a system reset is performed, a recalibration process may beinitiated where all current state information will be replaced based onnewly received input 22. Therefore, the effects of the errors in theoperational state information will be fully removed from the system.

In some implementations, the corrective action initiated by errorchecking logic 20 may include setting some or all of the operationalstate information within operational register 14 to a “safe” value thatwill not carry over into future operations. This may be performedwithout requiring a full system reset. For example, in oneimplementation, the state information stored within operational register14 may include information that hanks a peak magnetic field reading ofone or more sensor elements within system 10. If an error issubsequently identified within the state information, the peak magneticfield information may be reset to a low value that will not createerrors in the future (e.g., a value that is known to be lower thantypical peak magnetic field readings in the system). In some otherimplementations, the corrective action initiated by error checking logic20 may include sending an alert message to a user of system 10 to informthe user of the error(s) and to allow tire user to take furthercorrective action. As described above, in still other implementations,the state information within operational register 14 may be correctedusing the error correction capability of an error correction code. Othercorrective actions may alternatively be taken. In addition, combinationsof the above described corrective actions may alternatively be used.

Although described above as separate registers, it should be appreciatedthat the functions of operational register 14 and redundancy register 18may be realized using any of a wide variety of different data storageconfigurations. That is, these storage functions may be provided usingany type of digital data storage device, or combination of data storagedevices, that are capable of achieving the necessary storage andretrieval speeds. For example. In one approach, the functions ofoperational register 14 and redundancy register 18 may be realized usinga single register. In some embodiments, the functions of one or both ofthe registers 14, 18 may be realized using multiple separate datastorage devices and/or memory locations within system 10. The functionsof the two registers 14, 18 may, for example, be realized using multipledifferent locations within a common semiconductor memory device (e.g.,RAM memory, flash memory, etc.). Likewise, memory locations withindifferent semi conductor memories may be used. In some embodiments, flipflops may be used for operational register 14 and redundancy register18. Other forms of digital data storage, or combinations of differentforms of digital data storage, may be used in other implementations. Insome embodiments, analog storage may be used for the redundantinformation.

In at least one implementation, system 10 of FIG. 1 may be part of anintegrated circuit (IC) having a predetermined function. For example, inone implementation, system 10 may be included within a sensor IC for usein sensing one or more operational parameters of a larger system. Insome implementations, system 10 may be adapted for use within vehicularapplications that use sensors such as, for example, magnetic linear andangular position sensors, magnetic digital position sensors, currentsensors, magnetic speed sensors, and/or others. Each of these types ofsensors may make use of one or more magnetic field sensing elements,which may include, for example, Hall effect elements, magnetoresistanceelements, magnetotransistor elements, and/or others. In otherimplementations, system 10 may be adapted for use in non-vehicularapplications and/or non-sensor applications. In a non-sensorapplication, the inputs to operational logic 12 may be from a sourceother than a sensing element.

FIG. 2 is a flow diagram illustrating a process 30 for detecting andrecovering from errors in an electronic system in accordance with anembodiment.

The rectangular elements (typified by element 32 in FIG. 2) are hereindenoted “processing blocks” and may represent computer softwareinstructions or groups of instructions. It should be noted that the flowdiagram of FIG. 2 represents one exemplary embodiment of a designdescribed herein and variations in such a diagram, which generallyfollow the process outlined, are considered to be within the scope ofthe concepts, systems, and techniques described and claimed herein.

Alternatively, the processing blocks may represent operations or actionsperformed by functionally equivalent circuits such as, for example, adigital signal processor (DSP), an application specific integratedcircuit (ASIC), a field programmable gate array (FPGA), or othercircuitry. Some processing blocks may be manually performed while otherprocessing blocks may be performed by a processor, a circuit, or othermachine. The flow diagram, does not depict the syntax of any particularprogramming language. Rather, the flow diagram illustrates thefunctional information one of ordinary skill in the art requires tofabricate circuits and/or to generate computer software to perform therequired processing. It should be noted that many routine programelements, such as initialization of loops and variables and the use oftemporary variables may not be shown. It will be appreciated by those ofordinary skill in the art that unless otherwise indicated herein, theparticular sequence described is illustrative only and can be variedwithout departing from the spirit of the concepts described and/orclaimed herein. Thus, unless otherwise stated, the processes describedbelow are unordered meaning that, when possible, the sequences shown inFIG. 2 can be performed in any convenient or desirable order.

Referring now to FIG. 2, process 30 will now be described. First, one ormore input signals may be received at the electronic system (block 32).The input signals may include, for example, measurements made of one ormore operational parameters using, for example, sensor elements or thelike. The inputs are next processed to determine a next operationalstate of the system (block 34). The next operational state of the systemmay then be stored within an operational register or other digitalstorage structure(s) (block 36). Once stored, the next operational stateinformation becomes the current operational state of the system. Thenext operational state information may also be processed to generateredundant information (block 38). The redundant information may bestored within, a redundancy register or other digital or analog storagestructure(s) (block 40). In some implementations, the next operationalstate information may be stored within the operational register atapproximately the same time that the redundant information is stored inthe redundancy register (e.g., in response to the same clock cycle).

The current operational state information stored in the operationalregister may subsequently be processed along with the redundantinformation stored in the redundancy register to determine whether oneor more errors exist (block 42). If one or more errors are detected,corrective action may be initiated (block 44-Y, 46). If no errors aredetected, method 30 may return to block 32 and the process may berepeated using newly received inputs. In a synchronous circuit, themethod 30 described above may be repeated once per clock cycle, in someimplementations. As described previously, the corrective action that isinitiated may include, for example, a full or partial system reset, arecalibration, setting some or all of the operational state informationwithin an operational register to a “safe” value, sending an alertmessage to a user of the system, correcting the system state informationusing an error correction code, and/or other actions, includingcombinations of the above.

Although described above in the context of sensors used in vehicularapplications, it should be appreciated that the systems, circuits,features, and techniques described herein may also be used in otherelectronics applications. These applications may include, for example,other sensor-related applications, LED driver circuit applications,motor driver circuit applications, regulator circuit applications,photoflash driver circuits applications, and/or others. In each of thesedifferent applications, the principles described herein may be used todetect errors within system state information caused by, for example,external stresses on the system, and to recover from those errors.

As used herein, the term “magnetic field sensing element” is used todescribe a variety of electronic elements that can sense a magneticfield. The magnetic field sensing element may include, but is notlimited to, a Hall effect, element, a magnetoresistance element, or amagnetotransistor. As is known, there are different types of Hall effectelements including, for example, planar Hall elements, vertical Hallelements, Circular Vertical Hall (CVH) elements, and others. As is alsoknown, there are different types of magnetoresistance elementsincluding, for example, a semiconductor magnetoresistance element suchas Indium Antimonide (InSb), a giant magnetoresistance (GMR) element, ananisotropic magnetoresistance element (AMR), a tunnelingmagnetoresistance (TMR) element, and a magnetic tunnel junction (MTJ).The magnetic field sensing element may be a single element or,alternatively, may include two or more magnetic field sensing elementsarranged in various configurations (e.g., a half bridge or foil(Wheatstone) bridge). Depending on the device type and other applicationrequirements, the magnetic field sensing element may be a device made ofa type IV semiconductor material such as Silicon (Si) or Germanium (Ge),or a type III-V semiconductor material like Gallium-Arsenide (GaAs) oran Indium compound, e.g., Indium-Antimonide (InSb).

As is known, some of the above-described magnetic field sensing elementsmay have an axis of maximum sensitivity parallel to a substrate thatsupports the magnetic field sensing element and some others may have anaxis of maximum sensitivity perpendicular to a substrate that supportsthe magnetic field sensing element. In particular, planar Hall elementstend to have axes of sensitivity perpendicular to a substrate, whilemetal based, or metallic magnetoresistance elements (e.g., GMR, TMR,AMR) and vertical Hall elements tend to have axes of sensitivityparallel to a substrate.

As used herein, the term “magnetic field sensor” is used to describe acircuit that uses a magnetic held sensing element, generally incombination with other circuits. Magnetic field sensors are used in avariety of applications, including, but not limited to, an angle sensorthat senses an angle of a direction of a magnetic field, a currentsensor that senses a magnetic field generated by a current carried by acurrent-carrying conductor, a magnetic switch that senses the proximityof a ferromagnetic object, a rotation detector that senses passingferromagnetic articles, for example, magnetic domains of a ring magnetor a ferromagnetic target (e.g., gear teeth) where the magnetic fieldsensor is used, in combination with a back-biased or other magnet, and amagnetic field sensor that senses a magnetic field density of a magneticfield.

Having described exemplary embodiments of the invention, it will nowbecome apparent to one of ordinary skill in the art that otherembodiments incorporating their concepts may also be used. Theembodiments contained herein should not be limited to disclosedembodiments bat rather should be limited only by the spirit and scope ofthe appended claims. All publications and references cited herein areexpressly incorporated herein by reference in their entirety.

What is claimed is:
 1. An electronic sensor system for use in anenvironment prone to mechanical and electrical overstress conditions,comprising: at least one sensor element to measure one or moreoperational parameters of the electronic sensor system; first digitalstorage circuitry to store a current operational state of the electronicsensor system, wherein the current operational state information storedin the first digital circuitry can include one or more errors caused bymechanical and overstress conditions; operational logic to determine anext operational state of the electronic sensor system based, at leastin part, on an input signal from the at least one sensor element;redundancy logic to generate redundant information associated with thenext operational state determined by the operational logic; seconddigital storage circuitry to store the redundant information; and errorchecking logic to determine compatibility of the current operationalstate stored in the first digital storage circuitry with the redundantinformation stored in the second digital storage circuitry to determinewhether the current operational state information includes the one ormore errors, the error checking logic including correction logic toinitiate corrective action for the electronic system if the one or moreerrors is detected by the error checking logic.
 2. The electronic sensorsystem of claim 1, wherein: the correction logic is configured toinitiate a system reset of the electronic sensor system if an error isdetected by the error checking logic, wherein the system reset includesa recalibration process where all current state information is replacedbased on new input from the at least one sensor element.
 3. Theelectronic sensor system of claim 1, wherein: the correction logic isconfigured to send an alert to an operator of the electronic sensorsystem if an error is detected by the error checking logic.
 4. Theelectronic sensor system of claim 1, wherein: the correction logic isconfigured to modify the current operational state information stored inthe first digital storage circuitry to a safe state that will notproduce future errors in the electronic sensor system if an error isdetected by the error checking logic.
 5. The electronic sensor system ofclaim 1, wherein: the redundant information generated by the redundancylogic includes error correction coded redundant information; and thecorrection logic is configured to perform an error correction operationusing the error correction coded redundant information to correct thecurrent operational state information stored in the first digitalstorage circuitry if an error is detected by the error checking logic.6. The electronic sensor system of claim 1, wherein: the input signal ofthe operational logic is derived from an output signal of at least onesensing element that is operative for sensing features of a rotatingstructure.
 7. The electronic sensor system of claim 1, wherein: theinput signal of the operational logic is derived from an output signalof at least one magnetic field sensing element.
 8. The electronic sensorsystem of claim 7, wherein: the at least one magnetic field sensingelement includes at least one of: a Hall effect element, amagnetoresistance element, or a magnetotransistor.
 9. The electronicsensor system of claim 1, wherein: the redundant information generatedby the redundancy logic includes a parity bit.
 10. The electronic sensorsystem of claim 1, wherein: the redundant information generated by theredundancy logic includes a checksum.
 11. The electronic sensor systemof claim 1, wherein: the redundant information generated by theredundancy logic includes an error detection code.
 12. The electronicsensor system of claim 1, wherein: the redundant information generatedby the redundancy logic includes an error correction code.
 13. Theelectronic sensor system of claim 1, wherein: the redundant informationgenerated by the redundancy logic includes a full copy of the nextoperational state information determined by the operational logic. 14.The electronic sensor system of claim 1, wherein: the operational logicincludes at least one state machine.
 15. The electronic sensor system ofclaim 1, wherein: the operational logic is configured to determine thenext operational state of the electronic sensor system based on theinput signal and the current operational state of the electronic sensorsystem.
 16. The electronic sensor system of claim 1, wherein: the firstdigital storage circuitry is different from the second digital storagecircuitry.
 17. The electronic sensor system of claim 1, wherein: thefirst digital storage circuitry includes an operational register and thesecond digital storage circuitry includes a redundancy register that isdifferent from the operational register.
 18. A method for use indetecting and recovering from logic state errors in an electronic systemthat uses one or more sensor elements to measure operational parametersof the electronic system in an environment prone to mechanical andelectrical overstress conditions, comprising: receiving one or moreinput signals from one or more sensor elements; processing the one ormore input signals to determine a next operational state associated withthe electronic system; processing the next operational state informationto generate redundant information; storing the next operational stateinformation in first digital storage circuitry, the next operationalstate information becoming current operational state information oncestored, wherein the current operational state information stored in thefirst digital storage circuitry can include one or more errors caused bymechanical and electrical overstress conditions; storing the redundantinformation in second digital storage circuitry; determiningcompatibility of the operational state information with the storedredundant information to determine whether the one or more errors existin the stored operational state information; and initiating correctiveaction if the one or more errors are detected in the stored operationalstate information.
 19. The method of claim 18, further comprising:repeating receiving, processing the one or more input signals,processing the next operational state information, storing the nextoperational state information, storing the redundant information, andprocessing the stored operational state information with the storedredundant information if no errors are detected in the storedoperational state information.
 20. The method of claim 18, wherein:initiating corrective action includes initiating a system reset if oneor more errors are detected in the stored operational state information,wherein the system reset includes a recalibration process where allcurrent state information is replaced based on new input from the one ormore sensor elements.
 21. The method of claim 18, wherein: initiatingcorrective action includes sending an alert to an operator of theelectronic system if one or more errors are detected in the storedoperational state information.
 22. The method of claim 18, wherein:initiating corrective action includes modifying the stored operationalstate information to a safe state that will not produce future errors inthe electronic system if one or more errors are detected in the storedoperational state information.
 23. The method of claim 18, wherein:processing the next operational state information to generate redundantinformation includes using an error correctional code to generate errorcorrection coded redundant information; and initiating corrective actionincludes performing an error correction operation using the errorcorrection coded redundant information to correct the stored operationalstate information if one or more errors are detected in the storedoperational state information.
 24. The method of claim 18, wherein:receiving one or more inputs signals from one or more sensor elementsincludes receiving one or more inputs signals from a sensor element thatis operative for sensing features of a rotating structure.
 25. Themethod of claim 18, wherein: receiving one or more inputs signalsincludes receiving one or more inputs signals that are derived from anoutput signal of at least one magnetic field sensing element, the atleast one magnetic field sensing element including at least one of: aHall effect element, a magnetoresistance element, or amagnetotransistor.
 26. The method of claim 18, wherein: processing thenext operational state information to generate redundant informationincludes processing the next operational state information to generate aparity bit.
 27. The method of claim 18, wherein: processing the nextoperational state information to generate redundant information includesprocessing the next operational state information to generate achecksum.
 28. The method of claim 18, wherein: processing the nextoperational state information to generate redundant information includesprocessing the next operational state information to generate an errordetection codeword.
 29. The method of claim 18, wherein: processing thenext operational state information to generate redundant informationincludes processing the next operational state information to generatean error correction codeword.
 30. The method of claim 18, wherein:processing the next operational state information to generate redundantinformation includes making a copy of the next operational stateinformation.